PREHEAT oven to 350° F. Line 9-inch-square pan with foil.
FOR BROWNIE BASE:
MICROWAVE 1 1/4 cups morsels in small, uncovered, microwave-safe bowl on HIGH (100%) power for 1 minute; STIR. The morsels may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring just until morsels are melted. Set aside.
BEAT sugar and butter in large mixer bowl until creamy. Add eggs, vanilla extract and salt; mix well. Add melted chocolate and flour; mix well. Spread into prepared pan.
FOR CHEESECAKE TOPPING:
BEAT cream cheese, sugar and butter in large mixer bowl until creamy. Add eggs, milk, flour and vanilla extract; beat well. Stir in remaining 3/4 cup morsels. Pour over brownie base.
BAKE for 40 to 45 minutes or until center is set and top begins to brown lightly near the edges. Cool in pan on wire rack for 1 hour; refrigerate for at least 2 hours. Lift brownie from pan with foil; remove foil. Cut into bars. Store covered in refrigerator.
TIP: Brownies can be prepared in an 8-inch-square baking pan. Prepare as stated above but bake for 45 to 50 minutes. Bars will be thicker.